i seem to be able to at least play 720p @ 23.98 8bit uncompressed
with the current drive setup. that would be a striped pair of
sata drives. i haven't finished testing, but know i can't play
anything 1080psf 24 8bit or above. what are the minimum drive
formats for various digital formats? is there a table somewhere?

in other words, what would scsi, iscsi, fibre enable that i'm
not getting now? i'd probably look towards getting bare materials
and assembling my own rather than buying something like an xserve.

instead of saying "what is the minimum", how about listing what is the maximum you are trying to accomplish. Are you trying to do HDCam or SRW5500 4:4:4 uncompressed HD. Do you want 1080i uncompressed HD 10 bit, or do you want DVCProHD, or do you want HDV, or do you want DV ? Do you want it all ?

If you want it all, get a big mama disk drive array, that will cost you a lot of money. You will find, however, that you can "get away" with 2 SATA drives stripped RAID 0 inside your MAC Pro, and do everything up to DVCProHD. It will even do some Pro Res. And if you get a 5 bay SATA array, it will do all of this smoothly. If you want to do more - meaning uncompressed HD at 8 or 10 bit, now you need more drive, and a more expensive system. So you list what you actually want to do, and I will tell you the cheapest way to do it.

[BabaG]"thanks for the replies. the card seems to go up to uncomp
1080p 10bit so i'd love to be able to do that. what kind
of throughput does that require from my drives"

Did you download the data rate calculator? The throughput answer is there.

As for what to support it, I would say a very fast Fibre Channel array, possibly two striped together or two of these new super fast 8 to 10 bay SATA arrays. Probably in the neighborhood of $12,000 - $30,000 depending on the size of the storage.